WLANs are now in common use in both large and small businesses, as public Internet access points, and in home environments. Millions of access points and mobile units are now deployed. Enterprises commonly deploy wireless access points on one or more sub-networks often at multiple geographic locations. There also is a growing trend toward employing Wireless Local Area Network (WLAN) technology for public Internet access points used by travelers or other mobile users.
In a WLAN, one or more base stations or Access Points (AP) bridge between a wired network and radio frequency or infrared connections to one or more mobile stations or Mobile Units (MU). The MUs can be any of a wide variety of devices including, laptop computers, personal digital assistants, wireless bar code scanners, wireless point of sale systems or payment terminals, and many other specialized devices. Most WLAN systems used in business and public access environments adhere to one or more of the IEEE 802.11 family of specifications.
In a typical corporate environment the mobile units roam between the one or more sub-networks used by that enterprise. Often times, the environments and services for these sub-networks are significantly different. The configuration requirements for both hardware and software for the mobile units can therefore change significantly between sub-networks. Management of these configurations for large numbers of mobile units using a large number of sub-networks can be a significant problem. This problem is made more difficult by the fact that third party service providers operate some sub-networks used by the mobile units, while other networks are operated by the enterprise itself. Finally, any practical WLAN configuration management system must provide a method to update the software and configuration information on the mobile units.
Dynamic configuration management of nodes on local area networks is widely practiced. Several examples of well-established dynamic configuration management protocols are known. One widely deployed example is the BOOTP protocol (see RFC951) and its extensions (see for example RFC2132) that allow a server to configure parameters and load files onto a network node under management. However, these protocols, and the related Dynamic Host Configuration Protocol (DHCP; RFC2131) only operate at startup or boot time of the network node and do not attempt to control network access based on the configuration management policies.
Many standard network management tools include dynamic network node configuration management capabilities. Some examples of these tools include the OpenView from Hewlett Packard, the Tivioli network management products from IBM, and the Unicenter management product from Computer Associates. In all cases, these products rely on an existing network connection (i.e. sockets over a TCP/IP protocol) and therefore, none of these products can limit network access based on enforcement of configuration management policies.
U.S. Pat. No. 5,367,635 to Bauer and Kepke discloses a system using the Simple Network Management Protocol (SNMP) to manage configuration parameters and files on network nodes. This system requires an existing TCP/IP connection for SNMP sessions, and therefore cannot limit network access based on enforcement of configuration management policies.
In U.S. Pat. No. 5,651,006 to Fujino, et. al., a hierarchical network management system is disclosed, wherein one or more servers distributed over a hierarchy of sub-networks uses the SNMP protocols to manage the configurations of the nodes on a sub-network specific basis. This system requires an existing TCP/IP connection for SNMP sessions, and therefore cannot limit network access based on enforcement of configuration management policies.
U.S. Pat. No. 5,655,081 to Bonnell, et. al., discloses a system, wherein a network management server uses agents executing a set of specific scripts on network nodes to discover and manage the use of network services. This system requires an existing network connection or sessions (usually running over the TCP/IP protocol), and therefore cannot limit network access based on enforcement of configuration management policies.
U.S. Pat. No. 5,872,931 to Chivaluri discloses a system, wherein a hierarchy of management agents attempts to autonomously run corrective scripts when a fault is detected. This system does not attempt to limit network access based on enforcement and focuses on correction of fault rather than enforcement of configuration management policies.